The ability to detect a person in videos and video data has gained a good deal of importance in the last few years. This detection ability has applications in various fields, the most important of which is security and surveillance. Traditional security and/or surveillance systems are based on motion detection. Popular motion detection methods include passive infrared (PIR) detectors, ultrasound sensors, thermal imagers, and CMOS (complementary metal-oxide semiconductor) cameras. These methods rely on detection triggered by object movement in a scene, caused by humans, pets, vehicles, etc. CMOS camera-based systems offer some ability to differentiate between moving cars and humans, but the results are scene specific. That is, the extrinsic and intrinsic camera parameters have to be known in order to have reliable human detection.
The sensing of humans in video data is a challenging endeavor for a variety of reasons, and false alarms reduce the system reliability. Moving foliage, lighting variations, and shadows are some common causes of false detections. In an indoor home scenario, false alarms are triggered commonly by pets, window drape movement due to wind, or car or foliage movement outside a window that is within the field of view (FOV) of the camera. Furthermore, in a do-it-yourself (DIY) installation of a surveillance system, the extrinsic parameters of the video sensing device are unknown. In most cases, the camera is placed at a covert location, such as behind a flower vase, which may provide an incorrect view angle for human detection. Incorrect detection and frequent false alarms cause user frustration and low system confidence. Consequently, there is a need in security and/or surveillance systems to detect human presence with minimal false alarms, i.e. the system triggers only with the presence of a human in the FOV of the video sensing device and not due to other erroneous cases as previously described. Additionally, for a home security scenario, the detection method should provide near real-time results to alert the home owner and/or police so that appropriate actions can be taken.